Mulberry benefits: only post-meal glucose fell — fasting glucose, HbA1c and lipids did not

Key benefits

1. 01Early research

   Only post-meal glucose moved — and mostly it was the leaf, not the fruit

   2017, European Journal of Nutrition. The authors searched PubMed, PubMed Central, ScienceDirect, SciSearch and Thai databases, including 13 randomised controlled trials rated high quality by Jadad score.

   What fell:

   • Glucose at 30 min — MD −1.04 (95% CI −1.36 to −0.73)
   • Glucose at 60 min — MD −0.87 (95% CI −1.27 to −0.48)
   • Glucose at 90 min — MD −0.55 (95% CI −0.87 to −0.22)

   All three intervals exclude zero. The effect shrinking over time is consistent too — 1.04 → 0.87 → 0.55.

   What did not move:

   • Fasting blood sugar — no difference
   • HbA1c — no difference
   • HOMA-IR (insulin resistance) — no difference
   • Total cholesterol, triglycerides, LDL, HDL — no difference on any of the four

   No serious adverse effects were found in either arm.

   How to read this.

   First, post-meal glucose is about that one meal. HbA1c reflects average glucose over the past two to three months. A lower post-meal peak without a change in HbA1c can mean the curve of one meal shifted while the overall glucose burden did not. It is also possible the trials were too short for HbA1c to move.

   Second, lipids did not move at all — not one of the four. There is no support here for "mulberry is good for your blood vessels".

   Third, and most important — the authors' phrase is "products derived from M. alba". Far more of that research used the leaf than the fruit.

   Mulberry leaf contains 1-deoxynojirimycin (DNJ), which inhibits alpha-glucosidase, the gut enzyme that breaks down carbohydrate, slowing how fast sugar is absorbed. That is the same class of mechanism as the diabetes drug acarbose. A pattern of lower post-meal glucose with unchanged fasting glucose fits that mechanism exactly.

   But DNJ is a leaf compound, and evidence that the berry delivers it in comparable amounts is a separate question.

   The honest conclusion:

   • That mulberry leaf tea or extract lowers the post-meal glucose peak has 13 randomised trials behind it
   • Fasting glucose, HbA1c, insulin resistance and lipids did not change
   • Expecting the same from eating the berries goes past the evidence
   • The authors themselves wrote that "large-scale RCTs would be informative"

   [1]
2. 02Nutrition data

   36.4 mg of vitamin C and 1.85 mg of iron — inside 43 kcal

   Per 100 g of raw mulberries:

   • 43 kcal, protein 1.44 g, fat 0.39 g
   • Of 9.8 g of carbohydrate, 1.7 g is fibre, sugar 8.1 g
   • Vitamin C 36.4 mg — 40% of the requirement
   • Iron 1.85 mg — high among fruit
   • Vitamin K 7.8 µg, potassium 194 mg, calcium 39 mg
   • Riboflavin 0.101 mg, vitamin E 0.87 mg

   43 kcal is low even among berries — below blueberry (57 kcal) and grape (69 kcal), a little above strawberry (32 kcal).

   The 36.4 mg of vitamin C stands out. A 70 g handful gives 25 mg, 28% of the requirement.

   1.85 mg of iron is high for fruit — more than four times strawberry's 0.41 mg. It is non-haem iron, so absorption is low — but mulberry carries vitamin C alongside it, so the fruit supplies its own absorption helper.

   The purple is anthocyanin, the same family of pigment as in blueberry and aronia. It does show antioxidant activity in a test tube, but this site did not identify evidence that mulberry anthocyanin changes a health outcome in people.

   8.1 g of sugar is moderate for fruit. A 70 g handful is 5.7 g.

   Keeping is this fruit's weakness. Thin-skinned and full of water, it starts softening the moment it is picked — which is why you rarely see it in shops. It travels mostly frozen, or as juice, jam or liqueur.

   Processed forms are different foods.

   • Frozen — composition largely holds. It goes soft on thawing
   • Juice and syrup — sugar is added. An entirely different food from the table above
   • Jam — more sugar again

   It stains hands and clothes. Anthocyanin does not wash out easily.

3. 03Not established

   "Good for the eyes", "stops hair going grey" — no evidence was identified

   This entry sorts through claims that are not established.

   Several traditional claims attach to mulberry: "good for the eyes", "prevents greying", "tonifies the kidneys". It has a documented history of use in traditional East Asian medicine.

   This site's position should be clear. That there is a traditional use is a fact, and that fact is not in dispute. But this site counts as evidence only whether an outcome changed in a trial in people.

   First, "good for the eyes". Anthocyanin is usually the reason given. But the evidence linking anthocyanin to visual function mostly concerns bilberry extract, and even there the results are inconsistent. This site found no randomised trial in which feeding people mulberry changed visual function.

   Second, "stops hair going grey". Grey hair comes from declining melanocyte function in the follicle, driven mainly by age and genetics. There is no human evidence that a food reverses it.

   Third, the meta-analysis above did not address these claims at all. It looked at glucose and lipids, and lipids did not move.

   Does that mean there is no reason to eat mulberries? No. A fruit with 36.4 mg of vitamin C and 1.85 mg of iron in 43 kcal needs no further reason. That its season is short and it is hard to find is itself a reason to eat it when you can.

   But that is eating fruit, not a benefit — and this site keeps the two apart.

   One more thing — take care if you are on diabetes medication. If mulberry leaf products inhibit alpha-glucosidase, they overlap with drugs of the same class (acarbose, voglibose). Discuss the risk of hypoglycaemia with your doctor.

How to eat it well

What to watch out for